1. Field of the Invention
The present invention relates to an apparatus capable of using a film cartridge wherein a film is contained in a cartridge and a lead portion of the film is thrust and fed out of the cartridge.
2. Description of the Prior Art
Conventionally, a camera has been provided wherein such a film cartridge of a thrusting system is employed. Before the film cartridge is loaded in a camera body, the whole film including a lead portion of the film is contained in the cartridge, and when an initial loading is executed, which is done on a film loading in a camera body, a shaft of the film is driven, a lead portion of the film is thrust (film thrusting operation), and it is fed out to a leading film frame with being wound up around a winding spool. A perforation is formed on the film corresponding to each of a film frame so that each of a film frame is fed to an appropriate position for photographing, and a sensor for detecting the perforation is arranged on a camera body.
In a camera capable of using such a film cartridge of a thrusting system, it is able to control so that the leading first film frame exactly stops at a normal position by a perforation detection when an initial loading is executed.
Moreover, in a camera capable of using such a film cartridge of a thrusting system, it is able to use a used film cartridge by loading it again on a camera and feeding to a position of an unexposed frame after the film is rewound in its halfway such that not all frames are photographed (exposed). Rewinding a camera in such a way, the whole film including its lead portion is contained in the cartridge.
According to the U.S. Pat. No. 4,947,197 gazette, a film has to be wound around a flanged bobbin which is disposed inside of a cartridge in order that its lead portion can be fed out of the cartridge by thrusting, and the lead portion has to be projected out of the circumference of a flange so as to make it able to use a rewound film. Therefore, a notch is formed on a lead portion of a film, and ahead of notch is kept being projected out of the circumference of a flange.
As mentioned above, if a film having a notch on its leading portion is loaded on a camera that detects a perforation in order to detect a leading first film frame, the notch may be wrongly detected as a perforation, which may cause a failure of an initial loading.
Moreover, in such a camera capable of using the above-mentioned film cartridge, there is a case that an initial loading operation which should be executed by a film feeding mechanism on loading a cartridge in the camera, can not be executed (a failure of film thrusting) due to some condition. In such a case, a sequence for rewinding and taking out the film cartridge may be executed so as to proceed to a re-initial loading. When a perforation is not detected by a perforation detection sensor although an amount of fed film reaches a prescribed amount after starting an initial loading, it may be judged that the initial loading is not executed normally. This is a method for judging whether the initial loading is executed normally or not.
However, as a notch is formed on its lead portion in order to execute a thrusting operation, if a perforation detection function is designed to be executed soon after starting an initial loading, and judge whether the initial loading is executed normally or not, the notch of the film may be wrongly detected as a perforation. In such a case, a leading frame is not fed normally.
A perforation detection sensor can be designed to detect the notch and perforation both, and judge a second detection signal to be the signal of a first perforation. However, even in such a design, when a lead portion of a film is close to a perforation detection sensor, a film is not yet positioned and guided exactly in a width direction, so that a notch may not be detected.
A perforation detection sensor can be arranged so as to detect only the perforation, without detecting the notch, by making use of a difference between positions of the notch and perforation. Even in such a case, however, as a lead portion of a film is not yet positioned in a width direction at the moment, a perforation detection sensor may detect a notch and a perforation both.